title: Epidemiologic evidence that prior antimicrobial exposure decreases resistance to infection by antimicrobial-sensitive Salmonella.
abstract: Exposure to antimicrobials is known to increase the risk of infection with antimicrobial-resistant strains of Salmonella, but this effect has not been previously demonstrated with antimicrobial-sensitive strains. The effect of prior antimicrobial exposure was studied during a multistate outbreak of salmonellosis caused by an antimicrobial-sensitive strain of Salmonella havana: 19 (26%) of 72 persons infected had taken an antimicrobial within 30 days before onset of symptoms. Antimicrobial therapy was begun a mean of 15.9 days before and stopped a mean of 7.9 days before onset. In a case-control study, 11 (31%) of 35 case-patients had taken antimicrobials within 30 days of onset compared with 9 (13%) of 70 age- and neighborhood-matched controls (matched odds ratio, 4.3; 95% confidence interval, 1.3, 13.5). The association remained when controlled for the presence of underlying illness or immunosuppression. Prior antimicrobial exposure appears to increase the risk of infection with antimicrobial-sensitive and resistant strains of Salmonella. The delay between antimicrobial use and onset of symptoms suggests that the effect may be due to prolonged alteration of the colonic bacterial flora, resulting in decreased resistance to colonization.
authors.affiliation: Enteric Diseases Branch, Centers for Disease Control, Atlanta, GA 30333.
authors.forename: A T
authors.initials: AT
authors.lastname: Pavia
authors.forename: L D
authors.initials: LD
authors.lastname: Shipman
authors.forename: J G
authors.initials: JG
authors.lastname: Wells
authors.forename: N D
authors.initials: ND
authors.lastname: Puhr
authors.forename: J D
authors.initials: JD
authors.lastname: Smith
authors.forename: T W
authors.initials: TW
authors.lastname: McKinley
authors.forename: R V
authors.initials: RV
authors.lastname: Tauxe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D016022:Case-Control Studies; D002645:Chickens; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D004352:Drug Resistance, Microbial; D005260:Female; D005845:Georgia / Q000453:epidemiology; D006801:Humans; D007108:Immune Tolerance; D007223:Infant; D008297:Male; D008460:Meat; D008875:Middle Aged; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology; D012475:Salmonella / Q000187:drug effects*; D012478:Salmonella Food Poisoning / Q000209:etiology; D012480:Salmonella Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents